Stecher Adolf

Adolf Stecher; Inverter / Battery Problem Follow-up Thank you, Kalahari Meerkat, Scorp007, Justin and Stefan; for your response to my problem which eventually helped me to get my Fivestar inverter up and running. It was the suggested bypassing of the open battery circuit-breaker with an ~ 20 Ohm resistor for about 5-7 minutes that caused the initially flashing battery-charging symbol to go to steady and start the inverter charging the batteries. This happened last Friday after I received the inverter back from the supplier. Since then, I didn’t experience any further problems. It is good to know that there are knowledgeable professional on this forum who take the time and effort to listen to problems and to respond in a meaningful and practical way to resolve the issues at hand. Something I definitely cannot say about the inverter supplier. Thanks again to all of you. Adolf Stecher

Thank you Kalahari Meerkat for this additional suggestion, I understand your reasoning and will follow your procedure once I have the inverter back. Will keep you posted with the outcome. Keep well! Adolf

Hi Scorp007, thanks for your suggestion and explanation wrt parallel charging / balancing, it makes sense to me for initial charging with my 12Vdc charger. However, as my inverter is a 24Vdc model, I obviously need the batteries in series for operation. The Mecer technical LiFe battery spec. says "SOL-B-L-M200. No Parallel charging ability and max 4 in Series". Any way, its educational and encouraging to receive these kind of comments and helps me to see some light at the end of the tunnel. Will feedback with an explanation once my inverter is doing what it is supposed to do. Regards Adolf

Hi justin, Thank you for your proposal which I will try it as soon as I have the inverter back from testing. In the meantime I decided to install a balancer and hope this will be the end of my troubles. Also your input is much appreciated and I will let you know about the final outcome. Many thanks. Adolf

Hi Kalahari Meerkat, I did actually a battery load-test, over about two hours, using a 20 Ohm resistor in series with the batteries and the inverter to establish some idea about the load performance. Would this have pre-charged the inverter capacitors, as suggested by you? From your comment I deduce that you also think the problem lies with the batteries and using a balancer might be the solution. I much appreciate your comment. Thank you. Adolf

Hi Stefan, Thanks for your response. The open circuit voltage for battery A =13.76V and B=13.62V. I did charge the batteries independently to have both voltages as close as possible. As, according to the battery manufacturer, my 12V LiFe batteries are not suitable for parallel operation I cannot apply your balancing proposal. However, when bouncing my problem off with Mecer, they suggested a battery balancer too. I much appreciate you reply. Adol

I recently bought a new Fivestar 24V 3.5KVA 3.5KW 80A MPPT hybrid inverter for my UPS / solar system. The installation comprises the above inverter and two Mecer 12V200Ah Lithium Iron Phosphate Battery SOL-B-L-M200, Model: EC4S2P200. Both 12V batteries are wired in series and connected to the above inverter. Both batteries are fully charged and the open circuit voltage is 27.4Vdc. The 24V battery circuit is protected by a 100Adc circuit breaker. The rated NiFe battery charge / discharge current is 100Adc. Problem As soon as I close the 100Adc circuit breaker, the battery voltage at the inverter terminals drops to 0Vdc without an overload or short-circuit trip of the CB. The resistance between the inverter + / - terminals = 0.4 Ohm, which should result in a startup current not exceeding 67.5 Adc. However, I do not know the inverter dynamics during startup. The inverter display shows a flashing “bP” battery symbol. Assumption I assume that the actual inverter cold-start current (don't know the value) causes the battery management system (BMS) to shut down in order to protect the batteries. I only have a very basic understanding of a BMS's functionality. Request Kindly assist with advice as to how to resolve this problem.